Cellular Autoimmunity Research Articles

DNMT3A-related overgrowth syndrome presenting with immune thrombocytopenic purpura

Tatton-Brown-Rahman syndrome (TBRS) is characterized by overgrowth, cognitive deficiency, and distinctive facial features resulting from germline DNMT3A variants. This report describes a four-year-old female diagnosed with TBRS due to a de novo and novel heterozygous DNMT3A variant, NM_022552.5:c.1627G>C:p.(Gly543Arg). Alongside typical TBRS features, she had a history of hospitalization for immune thrombocytopenic purpura (ITP) at five months old. While ITP is clinically diagnosed and has multifactorial origins, studies have demonstrated its autoimmune and genetic components. DNMT3A protein, responsible for DNA methylation, regulates various cellular processes, including hematopoiesis and autoimmunity. It has been reported that ITP patients exhibit decreased expression of DNMT3A, and specific variants linked to decreased platelet counts have been identified in a murine model for TBRS. Additionally, some case reports have been described with multiple cytopenias and thrombocytopenia without hematologic malignancy. In conclusion, this report emphasizes for the first time the occurrence of ITP in a TBRS patient and suggests that autoimmune and hematologic disorders may need to be considered in the follow-up of these patients. However, further evidence is required to establish a direct correlation.

Insulin-degrading enzyme regulates insulin-directed cellular autoimmunity in murine type 1 diabetes.

Type 1 diabetes results from the destruction of pancreatic beta cells by autoreactive T cells. As an autoantigen with extremely high expression in beta cells, insulin triggers and sustains the autoimmune CD4+ and CD8+ T cell responses and islet inflammation. We have previously shown that deficiency for insulin-degrading enzyme (IDE), a ubiquitous cytosolic protease with very high affinity for insulin, induces endoplasmic reticulum (ER) stress and proliferation in islet cells and protects non-obese diabetic mice (NOD) from diabetes. Here we wondered whether IDE deficiency affects autoreactive CD8+ T cell responses to insulin and thereby immune pathogenesis in NOD mice. We find that Ide-/- NOD harbor fewer diabetogenic T cells and reduced numbers of CD8+ T cells recognizing the dominant autoantigen insulin and islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP). Using in vitro digestions and cellular antigen presentation assays, we show that generation of the dominant insulin epitope B15-23 involves both the proteasome and IDE. IDE deficiency attenuates MHC-I presentation of the immunodominant insulin epitope by beta cells to cognate CD8+ T cells. Consequently, Ide-/- islets display reduced susceptibility to autoimmune destruction upon grafting, and to killing by insulin-specific CD8+ T cells. Moreover, Ide-/- mice are partly resistant to disease transfer by CD8+ T cells specific for insulin but not for IGRP. Thus, IDE has a dual role in beta cells, regulating ER stress and proliferation while at the same time promoting insulin-directed autoreactive CD8+ T cell responses.

The role of autoimmune thyroid disorders in patients with alopecia areata

Objective: The aim of this study was to investigate the association of thyroid autoimmunity with alopecia areata (AA) by examining thyroid stimulating hormone (TSH) and thyroid autoantibody levels. In addition, to compare the epidemiologic data obtained with the data of our country. Methods: Our study was organized as a cross-sectional, retrospective study. The study was performed on patients between the ages of 2-65 years who were admitted to our outpatient clinic between 01.01.2008 and 31.12.2011, who were clinically or histopathological diagnosed with AA, examined for etiology and thyroid autoantibodies were requested. Patients under two years of age and over 65 years of age, patients with no thyroid autoantibodies and pregnant patients were excluded. Results were expressed as mean±standard deviation and median values. Mann-Whitney U test was used to compare TSH, anti-TG antibody (Anti-TG) and anti-TPO (Anti-TPO) antibody values in the variables of nail involvement, psychiatry, comorbidity and family history. Spearman correlation analysis was used to examine the relationships between age and disease duration and TSH, Anti-TPO and Anti-TG variables. Results: In our study, 65 (42.8%) of 152 patients were female and 87 (57.2%) were male. The ages of the patients ranged between 2-65 years and the mean age was 26.5±14.6 years. The mean age of females was 27.5±14.4 and 25.7±14.9 in males. Elevated thyroid autoantibodies were found in a total of 29 patients, 21 of whom were female and 8 of whom were male. Of these 29 patients, 10 had hypothyroidism, 2 had chronic thyroiditis and 3 had toxic multinodular goiter. 14 patients did not return after the examination at the internal medicine outpatient clinic, so the diagnosis of thyroid disease could not be reached. The mean TSH, Anti-TG and Anti-TPO values were 2.27±1.57, 29.2±99 and 71.5±2.2, respectively. When these values were analyzed separately as men and women, they were found to be 2.6±2.02, 41.8±1.23 and 134±2.8 in women and 1.99±1.03, 19.8±75.6 and 24.5±1.32 in men. There was a significant difference between men and women in terms of Anti-TG and Anti-TPO values (p=0.011 and p=0.001, respectively). A significant correlation was found between disease duration and Anti-TPO positivity (p=0.045); however, a similar relationship was not found between disease duration and Anti-TG positivity (p=0.34). Conclusions: As a result of this study, although there was a significant correlation between anti-TPO and duration of AA, the association between thyroid autoimmunity and AA was not found to be statistically significant. This may be due to the fact that humoral autoimmunity plays a role in thyroid autoimmunity and primarily cellular autoimmunity plays a role in AA. In addition, the epidemiologic data of our study were similar to the data of studies conducted in our country.

Association of the neonatal Fc receptor promoter variable number of tandem repeat polymorphism with immunoglobulin response in patients with chronic inflammatory demyelinating polyneuropathy.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune disease with humoral and cellular autoimmunity causing demyelination of peripheral nerves, commonly treated with intravenous immunoglobulins (IVIg). The neonatal Fc receptor (FcRn), encoded by the FCGRT gene, prevents the degradation of immunoglobulin G (IgG) by recycling circulating IgG. A variable number of tandem repeat (VNTR) polymorphism in the promoter region of the FCGRT gene is associated with different expression levels of mRNA and protein. Thus, patients with genotypes associated with relatively low FcRn expression may show a poorer treatment response to IVIg due to increased IVIg degradation. VNTR genotypes were analyzed in 144 patients with CIDP. Patients' clinical data, including neurological scores and treatment data, were collected as part of the Immune-Mediated Neuropathies Biobank registry. Most patients (n = 124, 86%) were VNTR 3/3 homozygotes, and 20 patients (14%) were VNTR 2/3 heterozygotes. Both VNTR 3/3 and VNTR 2/3 genotype groups showed no difference in clinical disability and immunoglobulin dosage. However, patients with a VNTR 2 allele were more likely to receive subcutaneous immunoglobulins (SCIg) than patients homozygous for the VNTR 3 allele (25% vs. 9.7%, p = 0.02) and were more likely to receive second-line therapy (75% vs. 54%, p = 0.05). The VNTR 2/3 genotype is associated with the administration of SCIg, possibly reflecting a greater benefit from SCIg due to more constant immunoglobulin levels without lower IVIg levels between the treatment circles. Also, the greater need for second-line treatment in VNTR 2/3 patients could be an indirect sign of a lower response to immunoglobulins.

Immunomodulatory Mechanism of Coronary Heart Disease and Related Therapeutic Applications and Prospects

Coronary heart disease is a type of heart disease caused by stenosis or occlusion of the coronary artery lumen. The typical symptoms are chest pain, chest tightness, and aggravation after activity. It is divided into two categories, chronic coronary disease (CAD) and acute coronary syndrome (ACS). The pathological basis of CHD is coronary atherosclerosis, immune factors (cellular immunity, humoral immunity, autoimmunity, complement system, cytokines, adhesion molecules and apoptosis, etc.) are involved in the formation and development of atherosclerosis. So far, its pathogenesis has not been fully understood and there is no effective and specific drug treatment in clinic. This article is based on existing literature and research on the impact of immune regulation on coronary heart disease. To investigate the role of the immune system in the treatment of atherosclerosis, we analyzed the causes of atherosclerosis. Through literature search, this paper found the influence of infectious, autoimmune and chemical factors on atherosclerosis, and sought corresponding treatment methods for the cardiovascular and cerebrovascular injuries caused by these factors.

Thinking Beyond Hypogammaglobinemia is a Good Strategy in Good Syndrome

Good syndrome was first described as the conjunction of thymoma and hypogammaglobulinemia. However, it has since been found to encompass cellular immune defects and autoimmunity in some patients. We aim to describe patients with Good syndrome seen at our institution.

T cell autoimmunity and immune regulation to desmoglein 3, a pemphigus autoantigen.

Pemphigus is a life-threatening autoimmune bullous disease mediated by anti-desmoglein IgG autoantibodies. Pemphigus is mainly classified into three subtypes: pemphigus vulgaris, pemphigus foliaceus, and paraneoplastic pemphigus. The pathogenicity of autoantibodies has been extensively studied. Anti-human CD20 antibody therapy targeting B cells emerged as a more effective treatment option compared to conventional therapy for patients with an intractable disease. On the other hand, autoreactive T cells are considered to be involved in the pathogenesis based on the test results of human leukocyte antigen association, autoreactive T cell detection, and cytokine profile analysis. Research on the role of T cells in pemphigus has continued to progress, including that on T follicular helper cells, which initiate molecular mechanisms involved in antibody production in B cells. Autoreactive T cell research in mice has highlighted the crucial roles of cellular autoimmunity and improved the understanding of its pathogenesis, especially in paraneoplastic pemphigus. The mouse research has helped elucidate novel regulatory mechanisms of autoreactive T cells, such as thymic tolerance to desmoglein 3 and the essential roles of regulatory T cells, Langerhans cells, and other molecules in peripheral tissues. This review focuses on the immunological aspects of autoreactive T cells in pemphigus by providing detailed information on various related topics.

Pathogenesis of Autoimmune Cytopenias in Inborn Errors of Immunity Revealing Novel Therapeutic Targets.

Autoimmune diseases are usually associated with environmental triggers and genetic predisposition. However, a few number of autoimmune diseases has a monogenic cause, mostly in children. These diseases may be the expression, isolated or associated with other symptoms, of an underlying inborn error of immunity (IEI). Autoimmune cytopenias (AICs), including immune thrombocytopenic purpura (ITP), autoimmune hemolytic anemia (AIHA), autoimmune neutropenia (AN), and Evans’ syndrome (ES) are common presentations of immunological diseases in the pediatric age, with at least 65% of cases of ES genetically determined. Autoimmune cytopenias in IEI have often a more severe, chronic, and relapsing course. Treatment refractoriness also characterizes autoimmune cytopenia with a monogenic cause, such as IEI. The mechanisms underlying autoimmune cytopenias in IEI include cellular or humoral autoimmunity, immune dysregulation in cases of hemophagocytosis or lymphoproliferation with or without splenic sequestration, bone marrow failure, myelodysplasia, or secondary myelosuppression. Genetic characterization of autoimmune cytopenias is of fundamental importance as an early diagnosis improves the outcome and allows the setting up of a targeted therapy, such as CTLA-4 IgG fusion protein (Abatacept), small molecule inhibitors (JAK-inhibitors), or gene therapy. Currently, gene therapy represents one of the most attractive targeted therapeutic approaches to treat selected inborn errors of immunity. Even in the absence of specific targeted therapies, however, whole exome genetic testing (WES) for children with chronic multilineage cytopenias should be considered as an early diagnostic tool for disease diagnosis and genetic counseling.

Islet Autoimmunity is Highly Prevalent and Associated With Diminished β-Cell Function in Patients With Type 2 Diabetes in the Grade Study.

Islet autoimmunity may contribute to β-cell dysfunction in type 2 diabetes (T2D). Its prevalence and clinical significance have not been rigorously determined. In this ancillary study to the Glycemia Reduction Approaches in Diabetes-A Comparative Effectiveness (GRADE) Study, we investigated the prevalence of cellular and humoral islet autoimmunity in patients with T2D duration 4·0±3·0 y, HbA1c 7·5±0·5% on metformin alone. We measured T cell autoreactivity against islet proteins, islet autoantibodies against GAD65, IA2, ZnT8, and β-cell function. Cellular islet autoimmunity was present in 41·3%, humoral islet autoimmunity in 13·5%, and both in 5·3%. β-cell function calculated as iAUC-CG and ΔC-peptide(0- 30)/Δglucose(0-30) from an oral glucose tolerance test was lower among T cell-positives (T+) than T cell-negatives (T-) using two different adjustments for insulin sensitivity (iAUC-CG: 13·2% [95% CI 0·3, 24·4%] or 11·4% [95% CI 0·4, 21·2%] lower; ΔC-peptide(0-30)/Δglucose(0-30)) 19% [95% CI 3·1, 32·3%] or 17·7% [95% CI 2·6, 30·5%] lower). T+ patients had 17% higher HbA1c (95% CI 0·07, 0·28) and 7·7 mg/dL higher fasting plasma glucose levels (95% CI 0·2,15·3) than T- patients. We conclude that islet autoimmunity is much more prevalent in T2D patients than previously reported. T cell-mediated autoimmunity is associated with diminished β-cell function and worse glycemic control.

A Compass to Guide Insights into TH17 Cellular Metabolism and Autoimmunity.

T cells rapidly convert their cellular metabolic requirements upon activation, switching to a highly glycolytic program to satisfy their increasingly complex energy needs. Fundamental metabolic differences have been established for the development of Foxp3+ T regulatory (Treg) cells versus TH17 cells, alterations of which can drive disease. TH17 cell dysregulation is a driver of autoimmunity and chronic inflammation, contributing to pathogenesis in diseases such as multiple sclerosis. A recent paper published in Cell by Wagner, et al. combined scRNA-seq and metabolic mapping data to interrogate potential metabolic modulators of TH17 cell pathogenicity. This Compass to TH17 cell metabolism highlights the polyamine pathway as a critical regulator of TH17/Treg cell function, signifying its potential as a therapeutic target.

Fulminant type 1 diabetes patients display high frequencies of IGRP-specific type 1 CD8+ T cells

The role of cellular autoimmunity in the pathogenesis of fulminant type 1 diabetes (FT1D) remains largely unknown. In this study, we performed an integrated assay using peripheral blood mononuclear cells to determine the islet antigen-specific CD8+ T cell responses in FT1D and compare the responses among acute-onset T1D (AT1D) and slowly progressive T1D (SP1D). IGRP- and ZnT8-specific IL-6, G-CSF, and TNF-α responses were significantly upregulated in patients with FT1D, while IGRP- and ZnT8-specific IP-10 responses were significantly upregulated in patients with AT1D than in non-diabetics (ND). Furthermore, the frequencies of IGRP-specific type 1 CD8+ cytotoxic T (Tc1) cells were significantly higher in the FT1D group than in the ND, SP1D, and AT1D groups. Additionally, IGRP-specific Tc1 cells were more abundant in the FT1D with HLA-A2 group than in the FT1D without A2 group. In conclusion, our study suggests that IGRP-specific CD8+ T cells significantly contribute to the pathogenesis of FT1D.

Ageing enhances cellular immunity to myeloperoxidase and experimental anti-myeloperoxidase glomerulonephritis.

ANCA-associated vasculitis (AAV) is an autoimmune disease characterized by small blood vessel inflammation, commonly affecting the kidneys and respiratory tract. It is unclear why the incidence of this condition increases with age. Previous studies in a passive antibody transfer system in aged mice have implicated innate effectors. To test the hypothesis that autoimmunity to myeloperoxidase (MPO), an autoantigen responsible for AAV, increases with age, anti-MPO autoimmunity was studied in murine models of active autoimmunity and disease induced by cellular immunity. Young (8 weeks) and aged (either 15 or 22 months) mice were immunized with whole proteins or peptides from ovalbumin, as a model foreign antigen, or MPO protein or peptides. Mice were subjected to a model of active anti-MPO glomerulonephritis. Cellular and humoral immune responses, and tissue inflammation were assessed. While cellular immunity to ovalbumin was diminished in aged mice, cellular autoimmunity to MPO and its immunodominant CD4+ and CD8+ T cell epitopes was increased after immunization with either MPO peptides or whole MPO protein, assessed by peptide and antigen-specific production of the pro-inflammatory cytokines IFN-γ and IL-17A. MPO-ANCA titres were not increased in aged mice compared with young mice. In experimental anti-MPO glomerulonephritis, cell-mediated injury was increased, likely due to CD4+ and CD8+ T cells, innate immunity and the increased vulnerability of aged kidneys. Heightened cellular immunity to MPO develops with ageing in mice and may contribute to the increased incidence and severity of AAV in older people.

Islet Autoimmunity is Highly Prevalent and Associated With Diminished Beta-Cell Function in Patients With Type 2 Diabetes in the Grade Study

Background: Islet autoimmunity may contribute to beta-cell dysfunction in type 2 diabetes (T2D). Its prevalence and clinical significance have not been rigorously determined. We investigated the prevalence of cellular and humoral islet autoimmunity in T2D and their relation to beta-cell function. Methods: The study was nested in the Glycemia Reduction Approaches in Diabetes – A Comparative Effectiveness (GRADE) study. Participants included 419 T2D patients (age 57·4±10·3 y [mean±SD], body mass index 33·6±6·2 kg/m2, diabetes duration 4·0±3·0 y, HbA1c 7·5±0·5%). We measured humoral (autoantibodies against GAD65, IA2, ZnT8) and cellular (T-cell autoreactivity against islet antigens) autoimmunity, beta-cell function (ratio of incremental area under the curve of C-peptide to that of glucose from 0–120 min of an oral glucose tolerance test [iAUC-CG]), and ratio of C-peptide to glucose from 0–30 min (∆C-peptide(0–30)/∆glucose(0–30)), and glycemic parameters. Findings: Cellular islet autoimmunity was present in 41·3%, humoral islet autoimmunity in 13·5%, and both in 5·3%. iAUC-CG and ∆C-peptide(0–30)/∆glucose(0–30) were lower among T-cell-positives than -negatives using two different adjustments for insulin sensitivity (iAUC-CG: 13·2% [95% CI 0·3, 24·4%] or 11·4% [95% CI 0·4, 21·2%] lower; ∆C-peptide(0–30)/∆glucose(0–30)) 19% [95% CI 3·1, 32·3%] or 17·7% [95% CI 2·6, 30·5%] lower). T-cell-positives had 0·17% higher HbA1c (95% CI 0·07,0·28) and 7·7 mg/dL higher fasting plasma glucose levels (95% CI 0·2,15·3) than T-cell-negatives. Interpretation: Islet autoimmunity is highly prevalent in patients with T2D. T-cell-mediated autoimmunity is associated with diminished beta-cell function and worse glycemic control. Funding Information: This study was funded by the NIH. This ancillary study to the GRADE study was independently funded by grant R01DK104832 (to AB and JPP) from the National Institute of Diabetes and Digestive and Kidney Diseases. The GRADE study is supported by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) of the National Institutes of Health under Award Number U01DK098246. The planning of GRADE was supported by a U34 planning grant from the NIDDK (U34-DK-088043). The American Diabetes Association supported the initial planning meeting for the U34 proposal. The National Heart, Lung, and Blood Institute and the Centers for Disease Control and Prevention also provided funding support. The Department of Veterans Affairs provided resources and facilities. Additional support was provided by grant numbers P30 DK017047, P30 DK020541-44, P30 DK020572, P30 DK072476, P30 DK079626, P30 DK092926, U54 GM104940, UL1 TR000439, UL1 TR000445, UL1 TR001108, UL1 TR001409, UL1 TR001449, UL1 TR002243, UL1 TR002345, UL1 TR002378, UL1 TR002489, UL1 TR002489, UL1 TR002529, UL1 TR002535, UL1 TR002537, and UL1 TR002548. Educational materials have been provided by the National Diabetes Education Program. Material support in the form of donated medications and supplies has been provided by Becton, Dickinson an Company, Bristol-Myers Squibb, Merck, NovoNordisk, Roche Diagnostics, and Sanofi. Declaration of Interests: The authors declare no conflicts of interest. Ethics Approval Statement: Nineteen centers obtained local Institutional Review Board approval for the ancillary study and contributed participants.

Distinct Phenotypes of Islet Antigen-Specific CD4+ T Cells Among the 3 Subtypes of Type 1 Diabetes.

Type 1 diabetes (T1D) is classified into 3 subtypes: acute-onset (AT1D), slowly progressive (SP1D), and fulminant (FT1D). The differences in the type of cellular autoimmunity within each subtype remain largely undetermined. To determine the type and frequency of islet antigen-specific CD4+ T cells in each subtype of T1D. Twenty patients with AT1D, 17 with SP1D, 18 with FT1D, and 17 persons without diabetes (ND). We performed an integrated assay to determine cellular immune responses and T-cell repertoires specific for islet antigens. This assay included an ex vivo assay involving a 48-hour stimulation of peripheral blood mononuclear cells with antigen peptides and an expansion assay involving intracytoplasmic cytokine analysis. The results of the ex vivo assay indicated that glutamic acid decarboxylase 65 (GAD65)-specific interleukin-6 and interferon-inducible protein-10 (IP-10) responses and preproinsulin (PPI)-specific IP-10 responses were significantly upregulated in AT1D compared with those of ND. Furthermore, GAD65- and PPI-specific granulocyte colony-stimulating factor responses were significantly upregulated in FT1D. Expansion assay revealed that GAD65- and PPI-specific CD4+ T cells were skewed toward a type 1 helper T (Th1)- cell phenotype in AT1D, whereas GAD65-specific Th2 cells were prevalent in SP1D. GAD65-specific Th1 cells were more abundant in SP1D with human leukocyte antigen-DR9 than in SP1D without DR9. FT1D displayed significantly less type 1 regulatory T (Tr1) cells specific for all 4 antigens than ND. The phenotypes of islet antigen-specific CD4+ T cells differed among the three T1D subtypes. These distinct T-cell phenotypes may be associated with the manner of progressive β-cell destruction.

254-OR: Islet Autoimmunity Is Highly Prevalent and Associated with Diminished Beta-Cell Function in Patients with Type 2 Diabetes (T2D) in the GRADE Study

We hypothesized that islet autoimmunity, hitherto considered the pathophysiologic basis of type 1 diabetes (T1D) and latent autoimmune diabetes of adults (LADA), could contribute to ß cell dysfunction in patients with type 2 diabetes (T2D). To evaluate this question, the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness (GRADE) Study - Beta Cell Ancillary Study Network measured humoral islet autoimmunity (autoantibodies against 65 kDa glutamic acid decarboxylase (GAD65-Ab), islet autoantigen-2 (IA2-Ab) and zinc transporter-8 (ZnT8-Ab)) in 392 participants (age 57.2 ± 10.1 y; BMI 33.5 ± 6.2 kg/m2; diabetes duration 4.0 ± 3.0 y; HbA1c 7.5 ± 0.5 %; on metformin as the sole glucose-lowering medication), and cellular islet autoimmunity (T cell autoreactivity against a broad range of islet antigens) in 322 of the same participants. 41.4% had evidence of cellular islet autoimmunity and 13.5% had evidence of humoral islet autoimmunity, but only 5.4% had both. T cell autoreactivity to islet antigens, but not autoantibody-positivity, was associated with diminished ß cell function, as assessed by the ratio of incremental area under the curve (iAUC) of C-peptide to iAUC of glucose during 0-120 min of an OGTT (ß = -0.1403; se = 0.0612; p = 0.0219) or ∆C-peptide/∆glucose during 0-30 min of an OGTT (ß = -0.2113; se = 0.0728; p = 0.0037), adjusted for insulin sensitivity. T cell positive participants also had higher fasting plasma glucose (p = 0.045) and HbA1c (p = 0.001) than T cell negative participants. These findings indicate that islet autoimmunity in T2D patients is far more prevalent than previously recognized; T cell mediated islet autoimmunity is associated with diminished ß cell function. Disclosure B. Brooks-Worrell: None. C.S. Hampe: None. E.V. Gonzalez: None. B.M. Palomino: None. S.Z. Zangeneh: None. K. Utzschneider: Other Relationship; Self; Medtronic. S.E. Kahn: Advisory Panel; Self; Boehringer Ingelheim International GmbH, Eli Lilly and Company, Intarcia Therapeutics, Janssen Scientific Affairs, LLC., Merck & Co., Inc., Novo Nordisk A/S, Pfizer Inc. M.E. Larkin: None. M.L. Johnson: Consultant; Self; Jaeb Center for Health Research. Research Support; Self; Abbott, Dexcom, Inc., Insulet Corporation, JDRF, Lilly Diabetes, Medtronic, National Institute of Diabetes and Digestive and Kidney Diseases, Novo Nordisk Inc. K.J. Mather: Research Support; Self; Abbott, Merck & Co., Inc., Novo Nordisk Inc., Sanofi. N. Younes: None. N. Rasouli: Advisory Panel; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Novo Nordisk Inc. Research Support; Self; Allergan plc., Novo Nordisk Inc. C. Desouza: Consultant; Self; AstraZeneca, Bayer AG, Novo Nordisk A/S. R.M. Cohen: Stock/Shareholder; Self; Bristol-Myers Squibb. J.Y. Park: None. H. Florez: None. W. Valencia: None. A. Shojaie: None. J.P. Palmer: None. A. Balasubramanyam: None. Funding National Institutes of Health (R01DK104832, U01DK098246)

USP29 maintains the stability of cGAS and promotes cellular antiviral responses and autoimmunity.

Cyclic GMP-AMP synthase (cGAS) is an essential sensor of cytosolic DNA and critically mediates innate immune responses and autoimmunity. Modulating the activity and stability of cGAS provides potential strategies for treating viral or autoimmune diseases. Here, we report that ubiquitin-specific protease 29 (USP29) deubiquitinates and stabilizes cGAS and promotes cellular antiviral responses and autoimmunity. Knockdown or knockout of USP29 severely impairs Herpes simplex virus 1 (HSV-1)- or cytosolic DNA-induced expression of type I interferons (IFNs) and proinflammatory cytokines. Consistently, Usp29m/m mice produce decreased type I IFNs and proinflammatory cytokines after HSV-1 infection and are hypersensitive to HSV-1 infection compared to the wild-type littermates. In addition, genetic ablation of USP29 in Trex1−/− mice eliminated the detectable pathological and molecular autoimmune phenotypes. Mechanistically, USP29 constitutively interacts with cGAS, deconjugates K48-linked polyubiquitin chains from cGAS and stabilizes cGAS in uninfected cells or after HSV-1 infection. Reconstitution of cGAS into Usp29−/− cells fully rescues type I IFN induction and cellular antiviral responses after HSV-1 infection. Our findings thus reveal a critical role of USP29 in the innate antiviral responses against DNA viruses and autoimmune diseases and provide insight into the regulation of cGAS.

SAT-673 Acute Onset Type 1 Diabetes Mellitus Caused by the Checkpoint Inhibitor Nivolumab

Background. Checkpoint inhibitors are monoclonal antibodies that augment immune system antitumor activity. Nivolumab is a checkpoint inhibitor that targets the programmed cell death receptor 1 (PD-1). Approximately 15% of patients treated with checkpoint inhibitors experience endocrine immune-related adverse events (irAEs), with autoimmune thyroid disorders and hypophysitis the most common endocrine irAEs. We present a case of acute onset type 1 diabetes mellitus (T1D) complicating treatment with nivolumab. Case. An 84 year old female received nivolumab (Opdivo) for metastatic small cell lung cancer. She tolerated twelve cycles of treatment well, but after the thirteenth cycle, she developed polydipsia and polyuria that prompted her to seek medical attention. Laboratories in the emergency department were notable for plasma glucose 998 mg/dL, bicarbonate 13 mM, anion gap 24, and strongly positive serum and urine ketones. An insulin infusion and parenteral fluids promptly resolved diabetic ketoacidosis (DKA), and the patient was then managed with subcutaneous basal/bolus insulin. Antibody markers (e.g. anti-GAD65) for T1D were undetectable, and evaluation for other endocrine irAEs was unremarkable. Given the rapid onset of DKA and the patient’s advanced age, she was diagnosed with nivolumab-induced T1D and discharged home on exogenous insulin. Conclusions. In a recent meta-analysis of 38 immune checkpoint inhibitor trials and over 7,500 patients, T1D was the least common endocrine irAE. The incidence of T1D was 0.2% compared to 6.6% for hypothyroidism, 2.9% for hyperthyroidism, 1.3% for hypophysitis, and 0.7% for primary adrenal insufficiency. All but one case (12/13) of T1D occurred in patients treated with a PD-1 inhibitor. Markers of both cellular and humoral diabetes-associated autoimmunity have been demonstrated in patients with T1D during treatment with nivolumab, and autoimmune destruction of beta-cells is the presumed etiology of diabetes. However, diabetes autoantibodies are detected in only about 50% of cases, and the absence of humoral markers does not exclude the diagnosis of nivolumab-induced T1D. There is a slight male predominance among published cases of nivolumab-induced T1D, and though median onset of T1D1 is after 11 weeks of treatment, there is a wide range of recorded times to T1D onset. Approximately 70% of patients present in DKA, and the significant majority of patients have undetectable or low C-peptide levels. Unfortunately, loss of beta-cell function persists after stopping nivolumab, and lifelong exogenous insulin is required for diabetes management. Though nivolumab-induced T1D is rare, the high risk of DKA as in this patient’s case illustrates the importance of recognizing nivolumab as a potential cause of autoimmune diabetes in older patients receiving anti-PD-1 immunotherapy.

Cytomegalovirus Induced Thrombocytopenia with No Platelets in an Immunocompetent Young Male

Introduction Immune thrombocytopenic purpura (ITP) is a common cause of acquired thrombocytopenia in an otherwise asymptomatic adult. It is generally believed to be caused by auto- antibodies against platelet antigens that destroy platelets peripherally and autoreactive cytotoxic T cells, as well as humoral and cellular autoimmunity directed at megakaryocytes, causing impaired platelet production. Cytomegalovirus (CMV) is a known cause of cause of morbidity and mortality in patients with immunosuppressed states, whereas in immunocompetent patients, it commonly manifest as asymptomatic or mononucleosis like syndrome. We are presenting a case of CMV induced thrombocytopenia with severe epistaxis and platelet count of 0 x10 9 in an otherwise healthy immunocompetent male who failed to improve after standard treatments with high dose steroids and intra venous immune globulin (IVIG). Case Description A 36-year-old Caucasian male without any past medical history presented to emergency room (ER) with flu like symptoms for five days associated with subjective fevers, anorexia, nausea, cough and weight loss of 15 lb. in two weeks. He also reported possible tick bite while working in the yard two days prior to admission. No dizziness, vomiting, diarrhea or any bleeding were reported. Denied any smoking, alcohol use or any illicit drug use. No significant family history was reported. On evaluation he was afebrile, normotensive with normal heart rate and respiratory rate. Physical examination was unremarkable. Initial laboratory data revealed hemoglobin of 11.2, platelet count 4 x109, white cell count of 13,100 with 4.5% atypical lymphocytes, aspartate aminotransferase of 41, alanine aminotransferase of 49, and creatinine of 1.4. He tested positive for Influenza A, CMV Immune globulin (Ig)M and IgG antibody. Serological tests for tick panel including anaplasma, babesia, Lyme disease and ehrlichia were negative. Epstein-Barr virus (EBV) antibody, parvo virus antibody, hepatitis screen, HIV screen, auto antibodies including anti-nuclear antibody and anti-double stranded DNA were negative. Coombs test was negative. Further work up includes ADAMTS13 activity was normal. No laboratory evidence of ADAMTS13 deficiency. After excluding all other causes, diagnosis of ITP was made. He was started on Tamiflu for Influenza A and high dose intra venous (IV) methyl prednisone for ITP. After platelet transfusion and two days of IV steroids platelet count improved 43 x 109 and he was discharged home with prolonged prednisone taper. Five days later, he presented to ER with severe epistaxis. Laboratory data revealed platelet count of 0 x109. Serum CMV-DNA was determined by PCR showed viral load of 8,790 copies/ml. Ultrasound abdomen showed mild splenomegaly. He received three doses of IVIG (1g/kg). Platelet count failed to improve after administration of IVIG. Bone marrow biopsy revealed hyper cellular marrow with trilineage hematopoiesis with no increase in CD 34 blasts. Per infectious disease and hematology recommendations, he was started on valganciclovir (900 mg PO BID). One month later, platelet count improved to 150 x 109 and CMV viral load dropped to 413 with subsequent resolution of patient's symptoms. Discussion Secondary ITP is an acquired thrombocytopenia caused by autoantibodies against platelets. Many patients with ITP are asymptomatic. For those who do have symptoms, initial presentations of ITP are petechiae, purpura and epistaxis, with a more severe progression to intracranial hemorrhage or gastrointestinal bleeding leading to a fatal outcome, if treatment is not started on a promptly manner. CMV induced thrombocytopenia in immunocompetent adults seems to be rare. we are presenting a case of CMV induced ITP which failed to improve after standard treatment with high dose steroids and IVIG but responded to anti-viral therapy with valganciclovir. In conclusion, it may be worthwhile to test for CMV infection in patients presenting with ITP. Further research is needed in order to establish treatment guidelines for CMV induced ITP in immunocompetent adults. Disclosures No relevant conflicts of interest to declare.

Abstract 127: The Lung-Associated Self-Antigen Type V Collagen is Regulated by Nuclear Factor of Activated T Cells Isoform c3 in Chronic Hypoxia

Chronic hypoxia (CH)-induced pulmonary hypertension (PH) is a progressive and often fatal consequence of chronic lung diseases, chronic exposure to high altitude and sleep apnea. PH results from arterial remodeling, enhanced vasoreactivity, and Th17 cell-mediated perivascular inflammation. Naturally occurring “nTH17” cells, can be detected in fetal life and are in homeostatic equilibrium with natural T regulatory cells. nTH17 cells are specific for a limited range of self-antigens, including type V collagen (colV). ColV is normally hidden from the immune system within type I col in the extracellular matrix of the lungs. We have shown that type V collagen is a self-antigen uncovered by CH. On the other hand, we have shown that mice lacking nuclear factor of activated T cells isoform c3 (NFATc3) globally and specifically in smooth muscle (SMC-NFATc3 KO) are protected from CH-induced PH. No differences in cardiac function were detected between SMC-NFATc3 KO and control mice using a Vevo LAZR-X ultrasound system before CH. In silico analysis of Col5A1 promoter shows NFATc3 binding sites. Therefore, we hypothesized that smooth muscle NFATc3 upregulates Col5A1 expression contributing to the development of acute autoreactivity to collagen V in response to CH, representing an upstream mechanism in PH development. Col5A1 was one of the 1792 genes differentially affected by both CH and smooth muscle NFATc3 in isolated pulmonary arteries (RNA Illumina Sequencing). Col5A1 mRNA increased significantly after 5 days of CH in control mice (fold change from normoxia±SD=2.2±0.8, n=5) vs. SMC-NFATc3 KO (0.8±0.3, n=3, p<0.03). Cellular autoimmunity to colV was determined using a trans-vivo delayed-type hypersensitivity assay (TV-DTH). Splenocytes from 5 days CH-exposed control mice displayed a TV-DTH colV response significantly higher than that from CH-exposed SMC-NFATc3 KO mice (footpad swelling [10 -4 ”] ± SD of naïve recipient mice injected with cells from CH control mice 25.6±4.2, n=8 vs. CH SMC-NFATc3 KO mice 5.3±0.5, n=7; p<0.0001). Our results suggest that smooth muscle NFATc3 is important for CH-induced PH in adult mice, in part, by regulating the expression of the lung self-antigen ColV contributing to pulmonary vascular inflammation.

Increase of Hspa1a and Hspa1b genes in the resting B cells of Sirt1 knockout mice.

Sirt1, also known as the longevity gene, is an NAD+-dependent class III histone deacetylase that has been extensively studied in multiple areas of research including cellular metabolism, longevity, cancer, autoimmunity, and immunity. However, little is known about the function of Sirt1 in B cells. This study aimed to investigate the role of Sirt1 in the expression pattern of mRNAs in the resting B cells of mice. CD19+ B cell-specific inducible Sirt1 knockout (KO) mice were divided into tamoxifen-treated Sirt1 KO group (S19T) or control group (S19). mRNAs extracted from resting B cells of both groups were analyzed for differentially expressed genes (DEG) using microarray. DEG analysis showed significant differential expression of 20 genes, of which Hspa1a and Hspa1b showed the highest fold change (FC) in S19T compared with S19 (p value < 0.01 and FC > 3). Further, Kyoto Encyclopedia of Genes and Genomes analysis identified pathways associated with diseases, organismal systems, and antigen processing and presentation. Additionally, the pathways known to involve Hspa1a and Hspa1b were also activated in the S19T group. On the other hand, after in vitro stimulation with lipopolysaccharide, cell viability and IgM production were significantly decreased in Sirt1 KO B cells, while expressions of TNF-α, IL-6, and IL-10 were increased. In summary, our study reveals that Sirt1 may maintain the quiescent state in resting B cells by suppressing the increase of Hspa1a and Hspa1b. This work provides a foundation for further studies on the functional roles of Sirt1 in B cells.